[AMX guy]

okay I pulled the transmission and I don't know what the problem is but I know where it is.

With it on the bench it turns freely and looks fine to me. but with it in neutral you cannot turn the input without the output turning as well. the sliders rattle and move and they are in neutral. there is a bit of slack between the input and output in the cluster. when you turn the cluster everything appears loose and moving freely. but something is serious wrong inside of it.

It had a kit put in it and it hadn't been used before I installed it and did the break in run on the cam. I put oil in it before starting the engine. is it possible a bearing inside the cluster was starved for lubrication during the break it? it worked fine just moving it around the shop but when I was getting ready to test drive it this all started.

[AMX guy]

Found the problem, don't know the solution.

the 1st synchro ring from the front was stuck on the hub. I took a screwdriver and popped it lose and now everything moves freely. this was a new kit with rings, should I assume they're junk and search for higher quality ones or could there be another cause?

[Formulas]

Sometimes welding on a car can send high current through strange places and do damage... you really can't see what's going on with the surfaces while it's together could be something that's new wasn't made quite perfect

[tempest1964]

New synchros can be out of round. They need to be checked for fit. There is an excellent video on this by a guy named Paul Cangualosi at 5speeds.com. The video explains it a lot better than me. Good luck!

[AMX guy]

Before I take it to someone I'm wondering if I should check the bellhousing alignment. could it be messes up enough to cause that synchro to bind on the hub? that would explain a lot. I could use one of the alignment tools in the future anyway.

the input fits in the pilot bushing easy and it bolts up no problem. but I don't know if that means anything. also, I did something kind of dumb , I put some silicone over the spot where the countershaft pin goes just to insure it didn't leak. about the thickness of 4 sheets of paper, I wonder it that may have had any effect on the alignment?

[mgarblik]

I would watch those gear box videos on Youtube. They are excellent. It's likely one or more brass rings are bent or warped. I do the Sharpie test he describes on all the gears and synchronizer rings now based on the video. About 1 out of three new ones are bad and can not be used. Junk parts make life tough on us. I bet you can fix this yourself. You just need a pair of really good heavy duty snap ring pliers and basic hand tools to take a Muncie apart. Very simple transmission. If you don't want to tackle it your self, PM me. I am doing 1 right now, a M22 for a guy from Indianapolis. I am in Dayton, OH.

[AMX guy]

Are there any high quality rings you can buy? I ran into problems using junk imported parts on an NP435 and luckily I found some NOS ones. I'm sure on a Muncie that's not an option.

I'll check that out.

[tempest1964]

Yes, Paul checks each set he sells. 100%. The videos are called The Muncie Tapes. On YouTube. There a 4 parts on YouTube. You can also call Paul. He’s a great guy and will answer any and all questions.

[Formulas]

So if his current problem is isolated to the forward syncro can he not just pull the input shat out of the front and install a new part..

No special tools just remove throw out collar pull input shaft collect the dropped out roller bearings position new syncro put roller bearings in place with a touch of grease reassemble with new gaskets with gasket thickness in mind for the bearing nut to collar relation..

The easiest syncro in the trans to replace on the fly

[AMX guy]

That would be nice if it's that easy, I'll watch the videos.

I'm going to look at things harder but I'm really starting to think I have an alignment issue. this is the original engine, bellhousing and transmission so I never checked the alignment. but one ear was broken on the transmission I had welded back on, and I think I see wear on the bellhousing opening. I suspect a problem there.

[Shiny]

Originally Posted by Formulas

Sometimes welding on a car can send high current through strange places and do damage... you really can't see what's going on with the surfaces while it's together could be something that's new wasn't made quite perfect

Originally Posted by AMX guy

That would be nice if it's that easy, I'll watch the videos.

I'm going to look at things harder but I'm really starting to think I have an alignment issue. this is the original engine, bellhousing and transmission so I never checked the alignment. but one ear was broken on the transmission I had welded back on, and I think I see wear on the bellhousing opening. I suspect a problem there.

This would be a good root cause...check the mating surfaces for signs of arcing or local heat damage?

[AMX guy]

I pulled the bearing retainer, and it fits snug in the bellhousing so that's not the problem.

I think I'll get some of those synchro's and order an alignment check tool.

[Shiny]

Originally Posted by AMX guy

Found the problem, don't know the solution.

the 1st synchro ring from the front was stuck on the hub. I took a screwdriver and popped it lose and now everything moves freely. this was a new kit with rings, should I assume they're junk and search for higher quality ones or could there be another cause?

Please help me understand how a stuck synchro caused the transmission to lock. Did it prevent the slider clutch from moving/disengaging?

If you could move the synchro with a screwdriver I doubt it would transmit enough torque to lock anything so I'm missing something....

Clearly something is wrong. I just want to understand the failure mode. This one has me curious as I don't understand how two gears could be engaged at once because of a synchro...

Here's a picture I found that helps me visualize. Where was the synchro bound up and how did it lock up the transmission hard enough to resist the engine?



Mike

[Formulas]

The syncro is keyed to the hub in 3 places so if syncro is locked with gear cone then its like shift collar is over all of them

does seem like the keys or syncro would bust or just loosen before locking chirping tires

[Shiny]

ignore.. I posted before Formula's edit

doh!

[Shiny]

Originally Posted by Formulas

The syncro is keyed to the hub in 3 places so if syncro is locked with gear cone then its like shift collar is over all of them

does seem like the keys or syncro would bust or just loosen before locking chirping tires

Thanks for this! I'm slow and still not seeing it, but it's been a long time since I was into a transmission. I have a Saginaw in the garage, will go look.

I thought all the torque went through the slider clutch (not sure of the right terminology) that moves on the hub when the shift fork pushes it... basically locking the hub to the gear. So if the synchro is locked to the hub, I'm not seeing how the mating gear was engaged and locked if the slider was either in neutral or engaging the other gear.

I guess if the synchro was locked to the gear (the tapered face), then it would try to transmit torque to the hub.... but again, if he loosened it with a screwdriver, how could it lock the gear against the engine torque ???

hmmm...

[AMX guy]

If I hadn't seen it myself I would question it too. it actually chirped the tires.

So I talked Paul at 5Speeds, very helpful and knowledgeable. He told me with the new syncros you need to polish and fit them or this can happen. he said I should be able to put it back in and wear them in by pushing on the shifter but not putting it in gear. he said my alignment would not be the cause since it's all original equipment.

I think I'm going to get a new set of rings and fit them properly since it's on my bench right now. I want to put new gaskets in with silicone it leaks bad now anyway.

[tstroud]

Buy your parts from Paul and watch “the Muncie tapes” on YouTube. He is a smart guy.

[AMX guy]

That's exactly what I'm doing. he explained it to me and told me to watch the video, it's exactly the problem I have, and I've never heard of it before.

He told me how to cure it and I didn't need to buy anything, but I'm going to put new rings in it and make sure they're working correct just so I know it's fixed. great guy. *

[77 TRASHCAN]

Paul wrote a book about working on Muncies. I "had" a copy, even though I'll never likely own a 4 speed car...
I'm sure the book is still in print, it's not that old...